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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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    <script>
        // var obj = {
        //     name: "张三",
        //     age: 15,
        //     tel: 110
        // }

        // for(let key in obj) {
        //     console.log(key)
        // }

        var arr = [1, 2, 3]

        // for(var key in arr) {
        //     console.log(key)
        // }
            // for ..of用来循环数组或者类数组对象 set和map结构的数据 以及字符串
            var str = 'hello'
        for(var value of str) {
            console.log(value)
        }
    </script>
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